Provided by: mkvtoolnix_45.0.0-2_amd64 
NAME
mkvmerge - Merge multimedia streams into a Matroska file
SYNOPSIS
mkvmerge [global options] {-o out} [options1] {file1} [[options2] {file2}]
[@options-file.json]
DESCRIPTION
This program takes the input from several media files and joins their streams (all of them
or just a selection) into a Matroska file; see the Matroska website[1].
Important
The order of command line options is important. Please read the section "Option order"
if you're new to the program.
Global options
-v, --verbose
Increase verbosity.
-q, --quiet
Suppress status output.
-o, --output file-name
Write to the file file-name. If splitting is used then this parameter is treated a bit
differently. See the explanation for the --split option for details.
-w, --webm
Create a WebM compliant file. This is also turned on if the output file name's
extension is "webm". This mode enforces several restrictions. The only allowed codecs
are VP8, VP9 video and Opus, Vorbis audio tracks. The DocType header item is changed
to "webm".
For chapters and tags only a subset of elements are allowed. mkvmerge(1) will
automatically remove all elements not allowed by the specification.
--title title
Sets the general title for the output file, e.g. the movie name.
--default-language language-code
Sets the default language code that will be used for tracks for which no language is
set with the --language option and for which the source container doesn't provide a
language.
The default language code is 'und' for 'undefined'.
Segment info handling (global options)
--segmentinfo filename.xml
Read segment information from a XML file. This file can contain the segment family
UID, segment UID, previous and next segment UID elements. An example file and a DTD
are included in the MKVToolNix distribution.
See the section about segment info XML files below for details.
--segment-uid SID1,SID2,...
Sets the segment UIDs to use. This is a comma-separated list of 128-bit segment UIDs
in the usual UID form: hex numbers with or without the "0x" prefix, with or without
spaces, exactly 32 digits.
If SID starts with = then its rest is interpreted as the name of a Matroska file whose
segment UID is read and used.
Each file created contains one segment, and each segment has one segment UID. If more
segment UIDs are specified than segments are created then the surplus UIDs are
ignored. If fewer UIDs are specified than segments are created then random UIDs will
be created for them.
Chapter and tag handling (global options)
--chapter-language language-code
Sets the ISO 639-2 language code that is written for each chapter entry. Defaults to
'eng'. See the section about chapters below for details.
This option can be used both for simple chapter files and for source files that
contain chapters but no information about the chapters' language, e.g. MP4 and OGM
files.
The language set with this option is also used when chapters are generated with the
--generate-chapters option.
--chapter-charset character-set
Sets the character set that is used for the conversion to UTF-8 for simple chapter
files. See the section about text files and character sets for an explanation how
mkvmerge(1) converts between character sets.
This switch does also apply to chapters that are copied from certain container types,
e.g. Ogg/OGM and MP4 files. See the section about chapters below for details.
--chapter-sync d[,o[/p]]
Adjust the timestamps of the chapters in the following source file by d ms.
Alternatively you can use the --sync option with the special track ID -2 (see section
special track IDs).
o/p: adjust the timestamps by o/p to fix linear drifts. p defaults to 1 if omitted.
Both o and p can be floating point numbers.
Defaults: no manual sync correction (which is the same as d = 0 and o/p = 1.0).
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
--generate-chapters mode
mkvmerge(1) can create chapters automatically. The following two modes are currently
supported:
• 'when-appending' – This mode creates one chapter at the start and one chapter
whenever a file is appended.
Note
mkvmerge(1) requires a video or an audio track to be present in order to be
able to determine when a new file is appended. If one or more video tracks are
muxed the first one is used. Otherwise the first audio track is used.
• 'interval:time-spec' – This mode creates one chapter at fixed intervals given by
time-spec. The format is either the form HH:MM:SS.nnnnnnnnn or a number followed
by one of the units 's', 'ms' or 'us'.
Example: --generate-chapters interval:45s
The names for the new chapters are controlled by the option
--generate-chapters-name-template. The language is set with --chapter-language which
must occur before --generate-chapters.
--generate-chapters-name-template template
This sets the name template for chapter names generated by the option
--generate-chapters. If the option is not used then default 'Chapter <NUM:2>' will be
used.
There are several variables that can be used in the template that are replaced by
their actual values when a chapter is generated. The string '<NUM>' will be replaced
by the chapter number. The string '<START>' will be replaced by the chapter's start
timestamp.
The strings '<FILE_NAME>' and '<FILE_NAME_WITH_EXT>' are only filled when generating
chapters for appended files. They will be replaced by the appended file's name wihtout
respectively with its extension. Note that only the file's base name and extension are
inserted, not its directory or drive components.
You can specify a minimum number of places for the chapter number with '<NUM:places>',
e.g. '<NUM:3>'. The resulting number will be padded with leading zeroes if the number
of places is less than specified.
You can control the format used by the start timestamp with <START:format>. The format
defaults to '%H:%M:%S' if none is given. Valid format codes are:
• %h – hours
• %H – hours zero-padded to two places
• %m – minutes
• %M – minutes zero-padded to two places
• %s – seconds
• %S – seconds zero-padded to two places
• %n – nanoseconds with nine places
• %<1-9>n – nanoseconds with up to nine places (e.g. three places with %3n)
--cue-chapter-name-format format
mkvmerge(1) supports reading CUE sheets for audio files as the input for chapters.
CUE sheets usually contain the entries PERFORMER and TITLE for each index entry.
mkvmerge(1) uses these two strings in order to construct the chapter name. With this
option the format used for this name can be set.
If this option is not given then mkvmerge(1) defaults to the format '%p - %t' (the
performer, followed by a space, a dash, another space and the title).
If the format is given then everything except the following meta characters is copied
as-is, and the meta characters are replaced like this:
• %p is replaced by the current entry's PERFORMER string,
• %t is replaced by the current entry's TITLE string,
• %n is replaced by the current track number and
• %N is replaced by the current track number padded with a leading zero if it is <
10.
--chapters file-name
Read chapter information from the file file-name. See the section about chapters below
for details.
--global-tags file-name
Read global tags from the file file-name. See the section about tags below for
details.
General output control (advanced global options)
--track-order FID1:TID1,FID2:TID2,...
This option changes the order in which the tracks for an input file are created. The
argument is a comma separated list of pairs IDs. Each pair contains first the file ID
(FID1) which is simply the number of the file on the command line starting at 0. The
second is a track ID (TID1) from that file. If some track IDs are omitted then those
tracks are created after the ones given with this option have been created.
--cluster-length spec
Limit the number of data blocks or the duration of data in each cluster. The spec
parameter can either be a number n without a unit or a number d postfixed with 'ms'.
If no unit is used then mkvmerge(1) will put at most n data blocks into each cluster.
The maximum number of blocks is 65535.
If the number d is postfixed with 'ms' then mkvmerge(1) puts at most d milliseconds of
data into each cluster. The minimum for d is '100ms', and the maximum is '32000ms'.
mkvmerge(1) defaults to putting at most 65535 data blocks and 5000ms of data into a
cluster.
Programs trying to find a certain frame can only seek directly to a cluster and have
to read the whole cluster afterwards. Therefore creating larger clusters may lead to
imprecise or slow seeking.
--no-cues
Tells mkvmerge(1) not to create and write the cue data which can be compared to an
index in an AVI. Matroska files can be played back without the cue data, but seeking
will probably be imprecise and slower. Use this only if you're really desperate for
space or for testing purposes. See also option --cues which can be specified for each
input file.
--clusters-in-meta-seek
Tells mkvmerge(1) to create a meta seek element at the end of the file containing all
clusters. See also the section about the Matroska file layout.
--no-date
By default mkvmerge(1) sets the "date" segment information field to the time & date
when multiplexing started. With this option that field is not written at all.
--disable-lacing
Disables lacing for all tracks. This will increase the file's size, especially if
there are many audio tracks. This option is not intended for everyday use.
--enable-durations
Write durations for all blocks. This will increase file size and does not offer any
additional value for players at the moment.
--disable-track-statistics-tags
Normally mkvmerge(1) will write certain tags with statistics for each track. If such
tags are already present then they will be overwritten. The tags are BPS, DURATION,
NUMBER_OF_BYTES and NUMBER_OF_FRAMES.
Enabling this option prevents mkvmerge(1) from writing those tags and from touching
any existing tags with same names.
--timestamp-scale factor
Forces the timestamp scale factor to factor. Valid values are in the range
1000..10000000 or the special value -1.
Normally mkvmerge(1) will use a value of 1000000 which means that timestamps and
durations will have a precision of 1ms. For files that will not contain a video track
but at least one audio track mkvmerge(1) will automatically chose a timestamp scale
factor so that all timestamps and durations have a precision of one audio sample. This
causes bigger overhead but allows precise seeking and extraction.
If the special value -1 is used then mkvmerge(1) will use sample precision even if a
video track is present.
File splitting, linking, appending and concatenation (more global options)
--split specification
Splits the output file after a given size or a given time. Please note that tracks can
only be split right before a key frame. Therefore the split point may be a bit off
from what the user has specified.
At the moment mkvmerge(1) supports four different modes.
1. Splitting by size.
Syntax: --split [size:]d[k|m|g]
Examples: --split size:700m or --split 150000000
The parameter d may end with 'k', 'm' or 'g' to indicate that the size is in KB,
MB or GB respectively. Otherwise a size in bytes is assumed. After the current
output file has reached this size limit a new one will be started.
The 'size:' prefix may be omitted for compatibility reasons.
2. Splitting after a duration.
Syntax: --split [duration:]HH:MM:SS.nnnnnnnnn|ds
Examples: --split duration:00:60:00.000 or --split 3600s
The parameter must either have the form HH:MM:SS.nnnnnnnnn for specifying the
duration in up to nano-second precision or be a number d followed by the letter
's' for the duration in seconds. HH is the number of hours, MM the number of
minutes, SS the number of seconds and nnnnnnnnn the number of nanoseconds. Both
the number of hours and the number of nanoseconds can be omitted. There can be up
to nine digits after the decimal point. After the duration of the contents in the
current output has reached this limit a new output file will be started.
The 'duration:' prefix may be omitted for compatibility reasons.
3. Splitting after specific timestamps.
Syntax: --split timestamps:A[,B[,C...]]
Example: --split timestamps:00:45:00.000,01:20:00.250,6300s
The parameters A, B, C etc must all have the same format as the ones used for the
duration (see above). The list of timestamps is separated by commas. After the
input stream has reached the current split point's timestamp a new file is
created. Then the next split point given in this list is used.
The 'timestamps:' prefix must not be omitted.
4. Keeping specific parts by specifying timestamp ranges while discarding others.
Syntax: --split parts:start1-end1[,[+]start2-end2[,[+]start3-end3...]]
Examples:
1. --split parts:00:01:20-00:02:45,00:05:50-00:10:30
2. --split parts:00:01:20-00:02:45,+00:05:50-00:10:30
3. --split parts:-00:02:45,00:05:50-
The parts mode tells mkvmerge(1) to keep certain ranges of timestamps while
discarding others. The ranges to keep have to be listed after the parts: keyword
and be separated by commas. A range itself consists of a start and an end
timestamp in the same format the other variations of --split accept (e.g. both
00:01:20 and 80s refer to the same timestamp).
If a start timestamp is left out then it defaults to the previous range's end
timestamp. If there was no previous range then it defaults to the start of the
file (see example 3).
If an end timestamp is left out then it defaults to the end of the source files
which basically tells mkvmerge(1) to keep the rest (see example 3).
Normally each range will be written to a new file. This can be changed so that
consecutive ranges are written to the same file. For that the user has to prefix
the start timestamp with a +. This tells mkvmerge(1) not to create a new file and
instead append the range to the same file the previous range was written to.
Timestamps will be adjusted so that there will be no gap in the output file even
if there was a gap in the two ranges in the input file.
In example 1 mkvmerge(1) will create two files. The first will contain the content
starting from 00:01:20 until 00:02:45. The second file will contain the content
starting from 00:05:50 until 00:10:30.
In example 2 mkvmerge(1) will create only one file. This file will contain both
the content starting from 00:01:20 until 00:02:45 and the content starting from
00:05:50 until 00:10:30.
In example 3 mkvmerge(1) will create two files. The first will contain the content
from the start of the source files until 00:02:45. The second file will contain
the content starting from 00:05:50 until the end of the source files.
Note
Note that mkvmerge(1) only makes decisions about splitting at key frame
positions. This applies to both the start and the end of each range. So even
if an end timestamp is between two key frames mkvmerge(1) will continue
outputting the frames up to but excluding the following key frame.
5. Keeping specific parts by specifying frame/field number ranges while discarding
others.
Syntax: --split parts-frames:start1-end1[,[+]start2-end2[,[+]start3-end3...]]
Examples:
1. --split parts-frames:137-258,548-1211
2. --split parts-frames:733-912,+1592-2730
3. --split parts-frames:-430,2512-
The parts-frames mode tells mkvmerge(1) to keep certain ranges of frame/field
numbers while discarding others. The ranges to keep have to be listed after the
parts-frames: keyword and be separated by commas. A range itself consists of a
start and an end frame/field number. Numbering starts at 1.
If a start number is left out then it defaults to the previous range's end number.
If there was no previous range then it defaults to the start of the file (see
example 3).
If an end number is left out then it defaults to the end of the source files which
basically tells mkvmerge(1) to keep the rest (see example 3).
Normally each range will be written to a new file. This can be changed so that
consecutive ranges are written to the same file. For that the user has to prefix
the start number with a +. This tells mkvmerge(1) not to create a new file and
instead append the range to the same file the previous range was written to.
Timestamps will be adjusted so that there will be no gap in the output file even
if there was a gap in the two ranges in the input file.
Note
Note that mkvmerge(1) only makes decisions about splitting at key frame
positions. This applies to both the start and the end of each range. So even
if an end frame/field number is between two key frames mkvmerge(1) will
continue outputting the frames up to but excluding the following key frame.
In example 1 mkvmerge(1) will create two files. The first will contain the content
starting from the first key frame at or after 137 up to but excluding the first
key frame at or after 258. The second file will contain the content starting from
548 until 1211.
In example 2 mkvmerge(1) will create only one file. This file will contain both
the content starting from 733 until 912 and the content starting from 1592 until
2730.
In example 3 mkvmerge(1) will create two files. The first will contain the content
from the start of the source files until 430. The second file will contain the
content starting from 2512 until the end of the source files.
This mode considers only the first video track that is output. If no video track
is output no splitting will occur.
Note
The numbers given with this argument are interpreted based on the number of
Matroska blocks that are output. A single Matroska block contains either a
full frame (for progressive content) or a single field (for interlaced
content). mkvmerge does not distinguish between those two and simply counts
the number of blocks. For example: If one wanted to split after the 25th full
frame with interlaced content one would have to use 50 (two fields per full
frame) as the split point.
6. Splitting after specific frames/fields.
Syntax: --split frames:A[,B[,C...]]
Example: --split frames:120,237,891
The parameters A, B, C etc must all be positive integers. Numbering starts at 1.
The list of frame/field numbers is separated by commas. After the input stream has
reached the current split point's frame/field number a new file is created. Then
the next split point given in this list is used.
The 'frames:' prefix must not be omitted.
This mode considers only the first video track that is output. If no video track
is output no splitting will occur.
Note
The numbers given with this argument are interpreted based on the number of
Matroska blocks that are output. A single Matroska block contains either a
full frame (for progressive content) or a single field (for interlaced
content). mkvmerge does not distinguish between those two and simply counts
the number of blocks. For example: If one wanted to split after the 25th full
frame with interlaced content one would have to use 50 (two fields per full
frame) as the split point.
7. Splitting before specific chapters.
Syntax: --split chapters:all or --split chapters:A[,B[,C...]]
Example: --split chapters:5,8
The parameters A, B, C etc must all be positive integers. Numbering starts at 1.
The list of chapter numbers is separated by commas. Splitting will occur right
before the first key frame whose timestamp is equal to or bigger than the start
timestamp for the chapters whose numbers are listed. A chapter starting at 0s is
never considered for splitting and discarded silently.
The keyword all can be used instead of listing all chapter numbers manually.
The 'chapters:' prefix must not be omitted.
Note
The Matroska file format supports arbitrary deeply nested chapter structures
called 'edition entries' and 'chapter atoms'. However, this mode only
considers the top-most level of chapters across all edition entries.
For this splitting mode the output filename is treated differently than for the normal
operation. It may contain a printf like expression '%d' including an optional field
width, e.g. '%02d'. If it does then the current file number will be formatted
appropriately and inserted at that point in the filename. If there is no such pattern
then a pattern of '-%03d' is assumed right before the file's extension: '-o
output.mkv' would result in 'output-001.mkv' and so on. If there's no extension then
'-%03d' will be appended to the name.
--link
Link files to one another when splitting the output file. See the section on file
linking below for details.
--link-to-previous segment-UID
Links the first output file to the segment with the segment UID given by the
segment-UID parameter. See the section on file linking below for details.
If SID starts with = then its rest is interpreted as the name of a Matroska file whose
segment UID is read and used.
--link-to-next segment-UID
Links the last output file to the segment with the segment UID given by the
segment-UID parameter. See the section on file linking below for details.
If SID starts with = then its rest is interpreted as the name of a Matroska file whose
segment UID is read and used.
--append-mode mode
Determines how timestamps are calculated when appending files. The parameter mode can
have two values: 'file' which is also the default and 'track'.
When mkvmerge appends a track (called 'track2_1' from now on) from a second file
(called 'file2') to a track (called 'track1_1') from the first file (called 'file1')
then it has to offset all timestamps for 'track2_1' by an amount. For 'file' mode this
amount is the highest timestamp encountered in 'file1' even if that timestamp was from
a different track than 'track1_1'. In track mode the offset is the highest timestamp
of 'track1_1'.
Unfortunately mkvmerge cannot detect which mode to use reliably. Therefore it defaults
to 'file' mode. 'file' mode usually works better for files that have been created
independently of each other; e.g. when appending AVI or MP4 files. 'track' mode may
work better for sources that are essentially just parts of one big file, e.g. for VOB
and EVO files.
Subtitle tracks are always treated as if 'file' mode were active even if 'track' mode
actually is.
--append-to SFID1:STID1:DFID1:DTID1[,...]
This option controls to which track another track is appended. Each spec contains four
IDs: a file ID, a track ID, a second file ID and a second track ID. The first pair,
"source file ID" and "source track ID", identifies the track that is to be appended.
The second pair, "destination file ID" and "destination track ID", identifies the
track the first one is appended to.
If this option has been omitted then a standard mapping is used. This standard mapping
appends each track from the current file to a track from the previous file with the
same track ID. This allows for easy appending if a movie has been split into two parts
and both file have the same number of tracks and track IDs with the command mkvmerge
-o output.mkv part1.mkv +part2.mkv.
+
A single '+' causes the next file to be appended instead of added. The '+' can also be
put in front of the next file name. Therefore the following two commands are
equivalent:
$ mkvmerge -o full.mkv file1.mkv + file2.mkv
$ mkvmerge -o full.mkv file1.mkv +file2.mkv
[ file1 file2 ]
If multiple file names are contained in a pair of square brackets then the second and
all following files will be appended to the first file named within the brackets.
This is an alternative syntax to using '+' between the file names. Therefore the
following two commands are equivalent:
$ mkvmerge -o full.mkv file1.mkv + file2.mkv
$ mkvmerge -o full.mkv '[' file1.mkv file2.mkv ']'
=
Normally mkvmerge(1) looks for files in the same directory as an input file that have
the same base name and only differ in their running number (e.g. 'VTS_01_1.VOB',
'VTS_01_2.VOB', 'VTS_01_3.VOB' etc) and treats all of those files as if they were
concatenated into a single big file. This option, a single '=', causes mkvmerge not to
look for those additional files.
The '=' can also be put in front of the next file name. Therefore the following two
commands are equivalent:
$ mkvmerge -o full.mkv = file1.mkv
$ mkvmerge -o full.mkv =file1.mkv
( file1 file2 )
If multiple file names are contained in a pair of parenthesis then those files will be
treated as if they were concatenated into a single big file consisting of the content
of each of the files one after the other.
This can be used for e.g. VOB files coming from a DVD or MPEG transport streams. It
cannot be used if each file contains its own set of headers which is usually the case
with stand-alone files like AVI or MP4.
Putting a file name into parenthesis also prevents mkvmerge(1) from looking for
additional files with the same base name as described in option =. Therefore these two
command lines are equivalent:
$ mkvmerge -o out.mkv = file.mkv
$ mkvmerge -o out.mkv '(' file.mkv ')'
Several things should be noted:
1. There must be spaces both after the opening and before the closing parenthesis.
2. Every parameter between parenthesis is interpreted as a file name. Therefore all
options applying to this logical file must be listed before the opening
parenthesis.
3. Some shells treat parenthesis as special characters. Hence you must escape or
quote them as shown in the example above.
Attachment support (more global options)
--attachment-description description
Plain text description of the following attachment. Applies to the next --attach-file
or --attach-file-once option.
--attachment-mime-type MIME type
MIME type of the following attachment. Applies to the next --attach-file or
--attach-file-once option. A list of officially recognized MIME types can be found
e.g. at the IANA homepage[2]. The MIME type is mandatory for an attachment.
--attachment-name name
Sets the name that will be stored in the output file for this attachment. If this
option is not given then the name will be derived from the file name of the attachment
as given with the --attach-file or the --attach-file-once option.
--attach-file file-name, --attach-file-once file-name
Creates a file attachment inside the Matroska file. The MIME type must have been set
before this option can used. The difference between the two forms is that during
splitting the files attached with --attach-file are attached to all output files while
the ones attached with --attach-file-once are only attached to the first file created.
If splitting is not used then both do the same.
mkvextract(1) can be used to extract attached files from a Matroska file.
Options that can be used for each input file
-a, --audio-tracks [!]n,m,...
Copy the audio tracks n, m etc. The numbers are track IDs which can be obtained with
the --identify switch. They're not simply the track numbers (see section track IDs).
Default: copy all audio tracks.
Instead of track IDs you can also provide ISO 639-2 language codes. This will only
work for source files that provide language tags for their tracks.
Default: copy all tracks of this kind.
If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this
kind but the ones listed after the !.
-d, --video-tracks [!]n,m,...
Copy the video tracks n, m etc. The numbers are track IDs which can be obtained with
the --identify switch. They're not simply the track numbers (see section track IDs).
Default: copy all video tracks.
Instead of track IDs you can also provide ISO 639-2 language codes. This will only
work for source files that provide language tags for their tracks.
If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this
kind but the ones listed after the !.
-s, --subtitle-tracks [!]n,m,...
Copy the subtitle tracks n, m etc. The numbers are track IDs which can be obtained
with the --identify switch. They're not simply the track numbers (see section track
IDs). Default: copy all subtitle tracks.
Instead of track IDs you can also provide ISO 639-2 language codes. This will only
work for source files that provide language tags for their tracks.
If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this
kind but the ones listed after the !.
-b, --button-tracks [!]n,m,...
Copy the button tracks n, m etc. The numbers are track IDs which can be obtained with
the --identify switch. They're not simply the track numbers (see section track IDs).
Default: copy all button tracks.
Instead of track IDs you can also provide ISO 639-2 language codes. This will only
work for source files that provide language tags for their tracks.
If the IDs are prefixed with ! then the meaning is reversed: copy all tracks of this
kind but the ones listed after the !.
--track-tags [!]n,m,...
Copy the tags for tracks n, m etc. The numbers are track IDs which can be obtained
with the --identify switch (see section track IDs). They're not simply the track
numbers. Default: copy tags for all tracks.
If the IDs are prefixed with ! then the meaning is reversed: copy everything but the
IDs listed after the !.
-m, --attachments [!]n[:all|first],m[:all|first],...
Copy the attachments with the IDs n, m etc to all or only the first output file. Each
ID can be followed by either ':all' (which is the default if neither is entered) or
':first'. If splitting is active then those attachments whose IDs are specified with
':all' are copied to all of the resulting output files while the others are only
copied into the first output file. If splitting is not active then both variants have
the same effect.
The default is to copy all attachments to all output files.
If the IDs are prefixed with ! then the meaning is reversed: copy everything but the
IDs listed after the !.
-A, --no-audio
Don't copy any audio track from this file.
-D, --no-video
Don't copy any video track from this file.
-S, --no-subtitles
Don't copy any subtitle track from this file.
-B, --no-buttons
Don't copy any button track from this file.
-T, --no-track-tags
Don't copy any track specific tags from this file.
--no-chapters
Don't copy chapters from this file.
-M, --no-attachments
Don't copy attachments from this file.
--no-global-tags
Don't copy global tags from this file.
--chapter-charset character-set
Sets the charset that is used for the conversion to UTF-8 for chapter information
contained in the source file. See the section about text files and character sets for
an explanation how mkvmerge(1) converts between character sets.
--chapter-language language-code
Sets the ISO 639-2 language code that is written for each chapter entry. This option
can be used for source files that contain chapters but no information about the
chapters' languages, e.g. for MP4 and OGM files.
-y, --sync TID:d[,o[/p]]
Adjust the timestamps of the track with the id TID by d ms. The track IDs are the same
as the ones given with --identify (see section track IDs).
o/p: adjust the timestamps by o/p to fix linear drifts. p defaults to 1 if omitted.
Both o and p can be floating point numbers.
Defaults: no manual sync correction (which is the same as d = 0 and o/p = 1.0).
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
--cues TID:none|iframes|all
Controls for which tracks cue (index) entries are created for the given track (see
section track IDs). 'none' inhibits the creation of cue entries. For 'iframes' only
blocks with no backward or forward references ( = I frames in video tracks) are put
into the cue sheet. 'all' causes mkvmerge(1) to create cue entries for all blocks
which will make the file very big.
The default is 'iframes' for video and subtitle tracks and 'none' for audio tracks.
See also option --no-cues which inhibits the creation of cue entries regardless of the
--cues options used.
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
--default-track TID[:bool]
Sets the 'default' flag for the given track (see section track IDs) if the optional
argument bool is not present. If the user does not explicitly select a track himself
then the player should prefer the track that has his 'default' flag set. Only one
track of each kind (audio, video, subtitles, buttons) can have his 'default' flag set.
If the user wants no track to have the default track flag set then he has to set bool
to 0 for all tracks.
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
--forced-track TID[:bool]
Sets the 'forced' flag for the given track (see section track IDs) if the optional
argument bool is not present. A player must play all tracks for which this flag is set
to 1.
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
--blockadd TID:level
Keep only the BlockAdditions up to the level level for the given track. The default is
to keep all levels. This option only affects certain kinds of codecs like WAVPACK4.
--track-name TID:name
Sets the track name for the given track (see section track IDs) to name.
--language TID:language
Sets the language for the given track (see section track IDs). Both ISO 639-2 language
codes and ISO 639-1 country codes are allowed. The country codes will be converted to
language codes automatically. All languages including their ISO 639-2 codes can be
listed with the --list-languages option.
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
-t, --tags TID:file-name
Read tags for the track with the number TID from the file file-name. See the section
about tags below for details.
--aac-is-sbr TID[:0|1]
Tells mkvmerge(1) that the track with the ID TID is SBR AAC (also known as HE-AAC or
AAC+). This options is needed if a) the source file is an AAC file (not for a Matroska
file) and b) the AAC file contains SBR AAC data. The reason for this switch is that it
is technically impossible to automatically tell normal AAC data from SBR AAC data
without decoding a complete AAC frame. As there are several patent issues with AAC
decoders mkvmerge(1) will never contain this decoding stage. So for SBR AAC files this
switch is mandatory. The resulting file might not play back correctly or even not at
all if the switch was omitted.
If the source file is a Matroska file then the CodecID should be enough to detect SBR
AAC. However, if the CodecID is wrong then this switch can be used to correct that.
If mkvmerge wrongfully detects that an AAC file is SBR then you can add ':0' to the
track ID.
--reduce-to-core TID
Some audio codecs have a lossy core and optional extensions that implement lossless
decoding. This option tells mkvmerge(1) to only copy the core but not the extensions.
By default mkvmerge(1) copies both the core and the extensions.
Currently only DTS tracks are affected by this option. TrueHD tracks that contain an
embedded AC-3 core are instead presented as two separate tracks for which the user can
select which track to copy. For DTS such a scheme would not work as the HD extensions
cannot be decoded by themselves – unlike the TrueHD data.
--remove-dialog-normalization-gain TID
Some audio codecs contain header fields that tell the decoder or player to apply a
(usually negative) gain for dialog normalization. This option tells mkvmerge(1) to
remove or minimize that gain by modifying the corresponding header fields.
Currently only AC-3, DTS and TrueHD tracks are affected by this option.
--timestamps TID:file-name
Read the timestamps to be used for the specific track ID from file-name. These
timestamps forcefully override the timestamps that mkvmerge(1) normally calculates.
Read the section about external timestamp files.
--default-duration TID:x
Forces the default duration of a given track to the specified value. Also modifies the
track's timestamps to match the default duration. The argument x must be postfixed
with 's', 'ms', 'us', 'ns', 'fps', 'p' or 'i' to specify the default duration in
seconds, milliseconds, microseconds, nanoseconds, 'frames per second', 'progressive
frames per second' or 'interlaced frames per second' respectively. The number x itself
can be a floating point number or a fraction.
If the default duration is not forced then mkvmerge will try to derive the track's
default duration from the container and/or the encoded bitstream for certain track
types, e.g. AVC/H.264 or MPEG-2.
This option can also be used to change the FPS of video tracks without having to use
an external timestamp file.
--fix-bitstream-timing-information TID[:0|1]
Normally mkvmerge(1) does not change the timing information (frame/field rate) stored
in the video bitstream. With this option that information is adjusted to match the
container timing information. The container timing information can come from various
sources: from the command line (see option --default-duration), the source container
or derived from the bitstream.
Note
This has only been implemented for AVC/H.264 video tracks so far.
--nalu-size-length TID:n
Forces the NALU size length to n bytes. This parameter is only used if the AVC/H.264
elementary stream packetizer is used. If left out it defaults to 4 bytes, but there
are files that contain frames or slices that are all smaller than 65536 bytes. For
such files you can use this parameter and decrease the size to 2.
--compression TID:n
Selects the compression method to be used for the track. Note that the player also has
to support this method. Valid values are 'none', 'zlib' and 'mpeg4_p2'/'mpeg4p2'.
The compression method 'mpeg4_p2'/'mpeg4p2' is a special compression method called
'header removal' that is only available for MPEG4 part 2 video tracks.
The default for some subtitle types is 'zlib' compression. This compression method is
also the one that most if not all playback applications support. Support for other
compression methods other than 'none' is not assured.
Options that only apply to video tracks
-f, --fourcc TID:FourCC
Forces the FourCC to the specified value. Works only for video tracks in the 'MS
compatibility mode'.
--display-dimensions TID:widthxheight
Matroska files contain two values that set the display properties that a player should
scale the image on playback to: display width and display height. These values can be
set with this option, e.g. '1:640x480'.
Another way to specify the values is to use the --aspect-ratio or the
--aspect-ratio-factor option (see below). These options are mutually exclusive.
--aspect-ratio TID:ratio|width/height
Matroska files contain two values that set the display properties that a player should
scale the image on playback to: display width and display height. With this option
mkvmerge(1) will automatically calculate the display width and display height based on
the image's original width and height and the aspect ratio given with this option. The
ratio can be given either as a floating point number ratio or as a fraction
'width/height', e.g. '16/9'.
Another way to specify the values is to use the --aspect-ratio-factor or
--display-dimensions options (see above and below). These options are mutually
exclusive.
--aspect-ratio-factor TID:factor|n/d
Another way to set the aspect ratio is to specify a factor. The original aspect ratio
is first multiplied with this factor and used as the target aspect ratio afterwards.
Another way to specify the values is to use the --aspect-ratio or --display-dimensions
options (see above). These options are mutually exclusive.
--cropping TID:left,top,right,bottom
Sets the pixel cropping parameters of a video track to the given values.
--colour-matrix TID:n
Sets the matrix coefficients of the video used to derive luma and chroma values from
red, green and blue color primaries. The parameter n is an integer rangeing from 0 and
10.
Valid values and their meaning are:
0: GBR, 1: BT709, 2: unspecified, 3: reserved, 4: FCC, 5: BT470BG, 6: SMPTE 170M, 7:
SMPTE 240M, 8: YCOCG, 9: BT2020 non-constant luminance, 10: BT2020 constant luminance
--colour-bits-per-channel TID:n
Sets the number of coded bits for a colour channel. A value of 0 indicates that the
number of bits is unspecified.
--chroma-subsample TID:hori,vert
The amount of pixels to remove in the Cr and Cb channels for every pixel not removed
horizontally/vertically.
Example: For video with 4:2:0 chroma subsampling, the parameter should be set to
TID:1,1.
--cb-subsample TID:hori,vert
The amount of pixels to remove in the Cb channel for every pixel not removed
horizontally/vertically. This is additive with --chroma-subsample.
Example: For video with 4:2:1 chroma subsampling, the parameter --chroma-subsample
should be set to TID:1,0 and Cb-subsample should be set to TID:1,0.
--chroma-siting TID:hori,vert
Sets how chroma is sited horizontally/vertically (0: unspecified, 1: top collocated,
2: half).
--colour-range TID:n
Sets the clipping of the color ranges (0: unspecified, 1: broadcast range, 2: full
range (no clipping), 3: defined by MatrixCoefficients/TransferCharacteristics).
--colour-transfer-characteristics TID:n
The transfer characteristics of the video.
Valid values and their meaning are:
0: reserved, 1: ITU-R BT.709, 2: unspecified, 3: reserved, 4: gamma 2.2 curve, 5:
gamma 2.8 curve, 6: SMPTE 170M, 7: SMPTE 240M, 8: linear, 9: log, 10: log sqrt, 11:
IEC 61966-2-4, 12: ITU-R BT.1361 extended colour gamut, 13: IEC 61966-2-1, 14: ITU-R
BT.2020 10 bit, 15: ITU-R BT.2020 12 bit, 16: SMPTE ST 2084, 17: SMPTE ST 428-1; 18:
ARIB STD-B67 (HLG)
--colour-primaries TID:n
Sets the colour primaries of the video.
Valid values and their meaning are:
0: reserved, 1: ITU-R BT.709, 2: unspecified, 3: reserved, 4: ITU-R BT.470M, 5: ITU-R
BT.470BG, 6: SMPTE 170M, 7: SMPTE 240M, 8: FILM, 9: ITU-R BT.2020, 10: SMPTE ST 428-1,
22: JEDEC P22 phosphors
--max-content-light TID:n
Sets the maximum brightness of a single pixel (Maximum Content Light Level) in
candelas per square meter (cd/m²). The value of n should be a non-negtive integer.
--max-frame-light TID:n
Sets the maximum brightness of a single full frame (Maximum Frame-Average Light Level)
in candelas per square meter (cd/m²). The value of n should be a non-negtive integer.
--chromaticity-coordinates TID:red-x,red-y,green-x,green-y,blue-x,blue-y
Sets the red/green/blue chromaticity coordinates as defined by CIE 1931.
--white-colour-coordinates TID:x,y
Sets the white colour chromaticity coordinates as defined by CIE 1931.
--max-luminance TID:float
Sets the maximum luminance in candelas per square meter (cd/m²). The value should be
less than 9999.99.
--min-luminance TID:float
Sets the minimum luminance in candelas per square meter (cd/m²). The value should be
less than 999.9999.
--projection-type TID:method
Sets the video projection method used. Valid values are 0 (rectangular projection), 1
(equirectangular projection), 2 (cubemap projection) and 3 (mesh projection).
--projection-private TID:data
Sets private data that only applies to a specific projection. Data must be given as
hex numbers with or without the "0x" prefix, with or without spaces.
--projection-pose-yaw TID:float
Specifies a yaw rotation to the projection.
--projection-pose-pitch TID:float
Specifies a pitch rotation to the projection.
--projection-pose-roll TID:float
Specifies a roll rotation to the projection.
--field-order TID:n
Sets the field order for the video track with the track ID TID. The order must be one
of the following numbers:
0: progressive; 1: interlaced with top field displayed first and top field stored
first; 2: undetermined field order; 6: interlaced with bottom field displayed first
and bottom field stored first; 9: interlaced with bottom field displayed first and top
field stored first; 14: interlaced with top field displayed first and bottom field
stored first
--stereo-mode TID:n|keyword
Sets the stereo mode for the video track with the track ID TID. The mode can either be
a number n between 0 and 14 or one of these keywords:
'mono', 'side_by_side_left_first', 'top_bottom_right_first', 'top_bottom_left_first',
'checkerboard_right_first', 'checkerboard_left_first', 'row_interleaved_right_first',
'row_interleaved_left_first', 'column_interleaved_right_first',
'column_interleaved_left_first', 'anaglyph_cyan_red', 'side_by_side_right_first',
'anaglyph_green_magenta', 'both_eyes_laced_left_first', 'both_eyes_laced_right_first'.
Options that only apply to text subtitle tracks
--sub-charset TID:character-set
Sets the character set for the conversion to UTF-8 for UTF-8 subtitles for the given
track ID. If not specified the charset will be derived from the current locale
settings. Note that a charset is not needed for subtitles read from Matroska files or
from Kate streams, as these are always stored in UTF-8. See the section about text
files and character sets for an explanation how mkvmerge(1) converts between character
sets.
This option can be used multiple times for an input file applying to several tracks by
selecting different track IDs each time.
Other options
-i, --identify file-name
Will let mkvmerge(1) probe the single file and report its type, the tracks contained
in the file and their track IDs. If this option is used then the only other option
allowed is the filename.
The output format used for the result can be changed with the option
--identification-format.
-J file-name
This is a convenient alias for "--identification-format json --identify file-name".
-F, --identification-format format
Determines the output format used by the --identify option. The following formats are
supported: text (the default if this option isn't used) and json.
1. The text format is short and human-readable. It consists of one line per item
found (container, tracks, attachments etc.).
This format is not meant to be parsed. The output will be translated into the
language mkvmerge(1) uses (see also --ui-language).
2. The json format outputs a machine-readable JSON representation. This format
follows the JSON schema described in the following file:
mkvmerge-identification-output-schema-v12.json[3]
All versions of the JSON schema are available both online and in the released
source code archives.
--probe-range-percentage percentage
File types such as MPEG program and transport streams (.vob, .m2ts) require parsing a
certain amount of data in order to detect all tracks contained in the file. This
amount is 0.3% of the source file's size or 10 MB, whichever is higher.
If tracks are known to be present but not found then the percentage to probe can be
changed with this option. The minimum of 10 MB is built-in and cannot be changed.
-l, --list-types
Lists supported input file types.
--list-languages
Lists all languages and their ISO 639-2 code which can be used with the --language
option.
--priority priority
Sets the process priority that mkvmerge(1) runs with. Valid values are 'lowest',
'lower', 'normal', 'higher' and 'highest'. If nothing is given then 'normal' is used.
On Unix like systems mkvmerge(1) will use the nice(2) function. Therefore only the
super user can use 'higher' and 'highest'. On Windows all values are useable for every
user.
Selecting 'lowest' also causes mkvmerge(1) to select idle I/O priority in addition to
the lowest possible process priority.
--command-line-charset character-set
Sets the character set to convert strings given on the command line from. It defaults
to the character set given by system's current locale. This settings applies to
arguments of the following options: --title, --track-name and
--attachment-description.
--output-charset character-set
Sets the character set to which strings are converted that are to be output. It
defaults to the character set given by system's current locale.
-r, --redirect-output file-name
Writes all messages to the file file-name instead of to the console. While this can be
done easily with output redirection there are cases in which this option is needed:
when the terminal reinterprets the output before writing it to a file. The character
set set with --output-charset is honored.
--flush-on-close
Tells the program to flush all data cached in memory to storage when closing files
opened for writing. This can be used to prevent data loss on power outages or to
circumvent certain problems in the operating system or drivers. The downside is that
multiplexing will take longer as mkvmerge will wait until all data has been written to
the storage before exiting. See issues #2469 and #2480 on the MKVToolNix bug tracker
for in-depth discussions on the pros and cons.
--ui-language code
Forces the translations for the language code to be used (e.g. 'de_DE' for the German
translations). Entering 'list' as the code will cause the program to output a list of
available translations.
--abort-on-warnings
Tells the program to abort after the first warning is emitted. The program's exit code
will be 1.
--deterministic seed
Enables the creation of byte-identical files if the same version of mkvmerge(1) is
used with the same source files, the same set of options and the same seed. Note that
the "date" segment information field is not written in this mode.
The seed can be an arbitrary string and does not have to be a number.
The result of byte-identical files is only guaranteed under the following conditions:
1. The same version of mkvmerge(1) built with the same versions of libEBML and
libMatroska is used.
2. The source files used are byte-identical.
3. The same command line options are used in the same order (with the notable
exception of --output ...).
Using other versions of mkvmerge(1) or other command-line options may result in the
same byte-identical file but is not guaranteed to do so.
--debug topic
Turn on debugging for a specific feature. This option is only useful for developers.
--engage feature
Turn on experimental features. A list of available features can be requested with
mkvmerge --engage list. These features are not meant to be used in normal situations.
--gui-mode
Turns on GUI mode. In this mode specially-formatted lines may be output that can tell
a controlling GUI what's happening. These messages follow the format '#GUI#message'.
The message may be followed by key/value pairs as in
'#GUI#message#key1=value1#key2=value2...'. Neither the messages nor the keys are ever
translated and always output in English.
@options-file.json
Reads additional command line arguments from the file options-file. See the section
about option files for further information.
--capabilities
Lists information about optional features that have been compiled in and exit. The
first line output will be the version information. All following lines contain exactly
one word whose presence indicates that the feature has been compiled in. These
features are:
• 'FLAC' -- reading raw FLAC files and handling FLAC tracks in other containers,
e.g. Ogg or Matroska.
-h, --help
Show usage information and exit.
-V, --version
Show version information and exit.
USAGE
For each file the user can select which tracks mkvmerge(1) should take. They are all put
into the file specified with -o. A list of known (and supported) source formats can be
obtained with the -l option.
Important
The order of command line options is important. Please read the section "Option order"
if you're new to the program.
OPTION ORDER
The order in which options are entered is important for some options. Options fall into
two categories:
1. Options that affect the whole program and are not tied to any input file. These
include but are not limited to --command-line-charset, --output or --title. These can
appear anywhere on the command line.
2. Options that affect a single input file or a single track in an input file. These
options all apply to the following input file on the command line. All options
applying to the same input (or to tracks from the same input file) file can be written
in any order as long as they all appear before that input file's name. Examples for
options applying to an input file are --no-chapters or --chapter-charset. Examples for
options applying to a single track are --default-duration or --language.
The options are processed from left to right. If an option appears multiple times within
the same scope then the last occurrence will be used. Therefore the title will be set to
"Something else" in the following example:
$ mkvmerge -o output.mkv --title 'This and that' input.avi --title 'Something else'
The following example shows that using the --language option twice is OK because they're
used in different scopes. Even though they apply to the same track ID they apply to
different input files and therefore have different scopes:
$ mkvmerge -o output.mkv --language 0:fre français.ogg --language 0:deu deutsch.ogg
EXAMPLES
Let's assume you have a file called MyMovie.avi and the audio track in a separate file,
e.g. 'MyMovie.wav'. First you want to encode the audio to OggVorbis:
$ oggenc -q4 -oMyMovie.ogg MyMovie.wav
After a couple of minutes you can join video and audio:
$ mkvmerge -o MyMovie-with-sound.mkv MyMovie.avi MyMovie.ogg
If your AVI already contains an audio track then it will be copied as well (if mkvmerge(1)
supports the audio format). To avoid that simply do
$ mkvmerge -o MyMovie-with-sound.mkv -A MyMovie.avi MyMovie.ogg
After some minutes of consideration you rip another audio track, e.g. the director's
comments or another language to 'MyMovie-add-audio.wav'. Encode it again and join it up
with the other file:
$ oggenc -q4 -oMyMovie-add-audio.ogg MyMovie-add-audio.wav
$ mkvmerge -o MM-complete.mkv MyMovie-with-sound.mkv MyMovie-add-audio.ogg
The same result can be achieved with
$ mkvmerge -o MM-complete.mkv -A MyMovie.avi MyMovie.ogg MyMovie-add-audio.ogg
Now fire up mplayer and enjoy. If you have multiple audio tracks (or even video tracks)
then you can tell mplayer which track to play with the '-vid' and '-aid' options. These
are 0-based and do not distinguish between video and audio.
If you need an audio track synchronized you can do that easily. First find out which track
ID the Vorbis track has with
$ mkvmerge --identify outofsync.ogg
Now you can use that ID in the following command line:
$ mkvmerge -o goodsync.mkv -A source.avi -y 12345:200 outofsync.ogg
This would add 200ms of silence at the beginning of the audio track with the ID 12345
taken from 'outofsync.ogg'.
Some movies start synced correctly but slowly drift out of sync. For these kind of movies
you can specify a delay factor that is applied to all timestamps -- no data is added or
removed. So if you make that factor too big or too small you'll get bad results. An
example is that an episode I transcoded was 0.2 seconds out of sync at the end of the
movie which was 77340 frames long. At 29.97fps 0.2 seconds correspond to approx. 6
frames. So I did
$ mkvmerge -o goodsync.mkv -y 23456:0,77346/77340 outofsync.mkv
The result was fine.
The sync options can also be used for subtitles in the same manner.
For text subtitles you can either use some Windows software (like SubRipper) or the subrip
package found in transcode(1)'s sources in the 'contrib/subrip' directory. The general
process is:
1. extract a raw subtitle stream from the source:
$ tccat -i /path/to/copied/dvd/ -T 1 -L | tcextract -x ps1 -t vob -a 0x20 | subtitle2pgm -o mymovie
2. convert the resulting PGM images to text with gocr:
$ pgm2txt mymovie
3. spell-check the resulting text files:
$ ispell -d american *txt
4. convert the text files to a SRT file:
$ srttool -s -w -i mymovie.srtx -o mymovie.srt
The resulting file can be used as another input file for mkvmerge(1):
$ mkvmerge -o mymovie.mkv mymovie.avi mymovie.srt
If you want to specify the language for a given track then this is easily done. First find
out the ISO 639-2 code for your language. mkvmerge(1) can list all of those codes for
you:
$ mkvmerge --list-languages
Search the list for the languages you need. Let's assume you have put two audio tracks
into a Matroska file and want to set their language codes and that their track IDs are 2
and 3. This can be done with
$ mkvmerge -o with-lang-codes.mkv --language 2:ger --language 3:dut without-lang-codes.mkv
As you can see you can use the --language switch multiple times.
Maybe you'd also like to have the player use the Dutch language as the default language.
You also have extra subtitles, e.g. in English and French, and want to have the player
display the French ones by default. This can be done with
$ mkvmerge -o with-lang-codes.mkv --language 2:ger --language 3:dut --default-track 3 without-lang-codes.mkv --language 0:eng english.srt --default-track 0 --language 0:fre french.srt
If you do not see the language or default track flags that you've specified in
mkvinfo(1)'s output then please read the section about default values.
Turn off the compression for an input file.
$ mkvmerge -o no-compression.mkv --compression -1:none MyMovie.avi --compression -1:none mymovie.srt
TRACK IDS
Regular track IDs
Some of the options for mkvmerge(1) need a track ID to specify which track they should be
applied to. Those track IDs are printed by the readers when demuxing the current input
file, or if mkvmerge(1) is called with the --identify option. An example for such output:
$ mkvmerge -i v.mkv
File 'v.mkv': container: Matroska
Track ID 0: video (V_MS/VFW/FOURCC, DIV3)
Track ID 1: audio (A_MPEG/L3)
Do not confuse the track IDs that are assigned to the tracks that are placed in the output
MKV file with the track IDs of the input files. Only the input file track IDs are used for
options needing these values.
Also note that each input file has its own set of track IDs. Therefore the track IDs for
file 'file1.ext' as reported by 'mkvmerge --identify' do not change no matter how many
other input files are there or in which position 'file1.ext' is used.
Track IDs are assigned like this:
• AVI files: The video track has the ID 0. The audio tracks get IDs in ascending order
starting at 1.
• AAC, AC-3, MP3, SRT and WAV files: The one 'track' in that file gets the ID 0.
• Most other files: The track IDs are assigned in order the tracks are found in the file
starting at 0.
The options that use the track IDs are the ones whose description contains 'TID'. The
following options use track IDs as well: --audio-tracks, --video-tracks,
--subtitle-tracks, --button-tracks and --track-tags.
Special track IDs
There are several IDs that have special meaning and do not occur in the identification
output.
The special track ID '-1' is a wild card and applies the given switch to all tracks that
are read from an input file.
The special track ID '-2' refers to the chapters in a source file. Currently only the
--sync option uses this special ID. As an alternative to --sync -2:... the option
--chapter-sync ... can be used.
TEXT FILES AND CHARACTER SET CONVERSIONS
Note
This section applies to all programs in MKVToolNix even if it only mentions
mkvmerge(1).
Introduction
All text in a Matroska file is encoded in UTF-8. This means that mkvmerge(1) has to
convert every text file it reads as well as every text given on the command line from one
character set into UTF-8. In return this also means that mkvmerge(1)'s output has to be
converted back to that character set from UTF-8, e.g. if a non-English translation is used
with --ui-language or for text originating from a Matroska file.
mkvmerge(1) does this conversion automatically based on the presence of a byte order
marker (short: BOM) or the system's current locale. How the character set is inferred from
the locale depends on the operating system that mkvmerge(1) is run on.
Byte order markers (BOM)
Text files that start with a BOM are already encoded in one representation of UTF.
mkvmerge(1) supports the following five modes: UTF-8, UTF-16 Little and Big Endian, UTF-32
Little and Big Endian. Text files with a BOM are automatically converted to UTF-8. Any of
the parameters that would otherwise set the character set for such a file (e.g.
--sub-charset) is silently ignored.
Linux and Unix-like systems including macOS
On Unix-like systems mkvmerge(1) uses the setlocale(3) system call which in turn uses the
environment variables LANG, LC_ALL and LC_CYPE. The resulting character set is often one
of UTF-8 or the ISO-8859-* family and is used for all text file operations and for
encoding strings on the command line and for output to the console.
Windows
On Windows the default character set used for converting text files is determined by a
call to the GetACP() system call.
Reading the command line is done with the GetCommandLineW() function which already returns
a Unicode string. Therefore the option --command-line-charset is ignored on Windows.
Output to the console consists of three scenarios:
1. If the output is redirected with the option --redirect-output then the default charset
is UTF-8. This can be changed with --output-charset.
If the output is redirected with cmd.exe itself, e.g. with mkvinfo file.mkv >
info.txt, then the charset is always UTF-8 and cannot be changed.
Otherwise (when writing directly to the console) the Windows function WriteConsoleW()
is used and the option --output-charset is ignored. The console should be able to
output all Unicode characters for which the corresponding language support is
installed (e.g. Chinese characters might not be displayed on English Windows
versions).
Command line options
The following options exist that allow specifying the character sets:
• --sub-charset for text subtitle files and for text subtitle tracks stored in container
formats for which the character set cannot be determined unambiguously (e.g. Ogg
files),
• --chapter-charset for chapter text files and for chapters and file titles stored in
container formats for which the character set cannot be determined unambiguously (e.g.
Ogg files for chapter information, track and file titles etc; MP4 files for chapter
information),
• --command-line-charset for all strings on the command line,
• --output-charset for all strings written to the console or to a file if the output has
been redirected with the --redirect-output option. On non-Windows systems the default
for the output charset is the system's current charset. On Windows it defaults to
UTF-8 both for redirecting with --redirect-output and with cmd.exe itself, e.g.
mkvinfo file.mkv > info.txt.
OPTION FILES
An option file is a file mkvmerge(1) can read additional command line arguments from. This
can be used in order to circumvent certain limitations of the shell or the operating
system when executing external programs like a limited command line length.
An option file contains JSON-formatted data. Its content must be a valid JSON array
consisting solely of JSON strings. The file's encoding must be UTF-8. The file should not
start with a byte order marker (BOM), but if one exists, it will be skipped.
The rules for escaping special characters inside JSON are the ones in the official JSON
specification, RFC 7159[4].
The command line 'mkvmerge -o "my file.mkv" -A "a movie.avi" sound.ogg' could be converted
into the following JSON option file called e.g. 'options.json':
[
"-o",
"c:\\Matroska\\my file.mkv",
"--title",
"#65",
"-A",
"a movie.avi",
"sound.ogg"
]
SUBTITLES
There are several text and bitmap subtitle formats that can be embedded into Matroska.
Text subtitles must be recoded to UTF-8 so that they can be displayed correctly by a
player (see the section about text files and character sets for an explanation how
mkvmerge(1) converts between character sets). Kate subtitles are already encoded in UTF-8
and do not have to be re-encoded.
The following subtitle formats are supported at the moment:
• Subtitle Ripper (SRT) files
• Substation Alpha (SSA) / Advanced Substation Alpha scripts (ASS)
• Universal Subtitle Format (USF) files
• OggKate streams
• VobSub bitmap subtitle files
• PGS bitmap subtitle files as found on BluRay discs
FILE LINKING
Matroska supports file linking which simply says that a specific file is the predecessor
or successor of the current file. To be precise, it's not really the files that are linked
but the Matroska segments. As most files will probably only contain one Matroska segment
the following explanations use the term 'file linking' although 'segment linking' would be
more appropriate.
Each segment is identified by a unique 128 bit wide segment UID. This UID is automatically
generated by mkvmerge(1). The linking is done primarily via putting the segment UIDs
(short: SID) of the previous/next file into the segment header information. mkvinfo(1)
prints these SIDs if it finds them.
If a file is split into several smaller ones and linking is used then the timestamps will
not start at 0 again but will continue where the last file has left off. This way the
absolute time is kept even if the previous files are not available (e.g. when streaming).
If no linking is used then the timestamps should start at 0 for each file. By default
mkvmerge(1) does not use file linking. If you want that you can turn it on with the --link
option. This option is only useful if splitting is activated as well.
Regardless of whether splitting is active or not the user can tell mkvmerge(1) to link the
produced files to specific SIDs. This is achieved with the options --link-to-previous and
--link-to-next. These options accept a segment SID in the format that mkvinfo(1) outputs:
16 hexadecimal numbers between 0x00 and 0xff prefixed with '0x' each, e.g. '0x41 0xda 0x73
0x66 0xd9 0xcf 0xb2 0x1e 0xae 0x78 0xeb 0xb4 0x5e 0xca 0xb3 0x93'. Alternatively a shorter
form can be used: 16 hexadecimal numbers between 0x00 and 0xff without the '0x' prefixes
and without the spaces, e.g. '41da7366d9cfb21eae78ebb45ecab393'.
If splitting is used then the first file is linked to the SID given with
--link-to-previous and the last file is linked to the SID given with --link-to-next. If
splitting is not used then the one output file will be linked to both of the two SIDs.
DEFAULT VALUES
The Matroska specification states that some elements have a default value. Usually an
element is not written to the file if its value is equal to its default value in order to
save space. The elements that the user might miss in mkvinfo(1)'s output are the language
and the default track flag elements. The default value for the language is English
('eng'), and the default value for the default track flag is true. Therefore if you used
--language 0:eng for a track then it will not show up in mkvinfo(1)'s output.
ATTACHMENTS
Maybe you also want to keep some photos along with your Matroska file, or you're using SSA
subtitles and need a special TrueType font that's really rare. In these cases you can
attach those files to the Matroska file. They will not be just appended to the file but
embedded in it. A player can then show those files (the 'photos' case) or use them to
render the subtitles (the 'TrueType fonts' case).
Here's an example how to attach a photo and a TrueType font to the output file:
$ mkvmerge -o output.mkv -A video.avi sound.ogg \
--attachment-description "Me and the band behind the stage in a small get-together" \
--attachment-mime-type image/jpeg \
--attach-file me_and_the_band.jpg \
--attachment-description "The real rare and unbelievably good looking font" \
--attachment-mime-type application/octet-stream \
--attach-file really_cool_font.ttf
If a Matroska containing attachments file is used as an input file then mkvmerge(1) will
copy the attachments into the new file. The selection which attachments are copied and
which are not can be changed with the options --attachments and --no-attachments.
CHAPTERS
The Matroska chapter system is more powerful than the old known system used by OGM files.
The full specifications can be found at the Matroska website[1].
mkvmerge(1) supports two kinds of chapter files as its input. The first format, called
'simple chapter format', is the same format that the OGM tools expect. The second format
is a XML based chapter format which supports all of Matroska's chapter functionality.
The simple chapter format
This format consists of pairs of lines that start with 'CHAPTERxx=' and 'CHAPTERxxNAME='
respectively. The first one contains the start timestamp while the second one contains the
title. Here's an example:
CHAPTER01=00:00:00.000
CHAPTER01NAME=Intro
CHAPTER02=00:02:30.000
CHAPTER02NAME=Baby prepares to rock
CHAPTER03=00:02:42.300
CHAPTER03NAME=Baby rocks the house
mkvmerge(1) will transform every pair or lines into one Matroska ChapterAtom. It does not
set any ChapterTrackNumber which means that the chapters all apply to all tracks in the
file.
As this is a text file character set conversion may need to be done. See the section about
text files and character sets for an explanation how mkvmerge(1) converts between
character sets.
The XML based chapter format
The XML based chapter format looks like this example:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE Chapters SYSTEM "matroskachapters.dtd">
<Chapters>
<EditionEntry>
<ChapterAtom>
<ChapterTimeStart>00:00:30.000</ChapterTimeStart>
<ChapterTimeEnd>00:01:20.000</ChapterTimeEnd>
<ChapterDisplay>
<ChapterString>A short chapter</ChapterString>
<ChapterLanguage>eng</ChapterLanguage>
</ChapterDisplay>
<ChapterAtom>
<ChapterTimeStart>00:00:46.000</ChapterTimeStart>
<ChapterTimeEnd>00:01:10.000</ChapterTimeEnd>
<ChapterDisplay>
<ChapterString>A part of that short chapter</ChapterString>
<ChapterLanguage>eng</ChapterLanguage>
</ChapterDisplay>
</ChapterAtom>
</ChapterAtom>
</EditionEntry>
</Chapters>
With this format three things are possible that are not possible with the simple chapter
format:
1. The timestamp for the end of the chapter can be set,
2. chapters can be nested,
3. the language and country can be set.
The mkvtoolnix distribution contains some sample files in the doc subdirectory which can
be used as a basis.
The following lists the supported XML tags, their data types and, where appropriate, the
valid range for their values:
Chapters (master)
EditionEntry (master)
EditionUID (unsigned integer, valid range: 1 <= value)
EditionFlagHidden (unsigned integer, valid range: 0 <= value <= 1)
EditionFlagDefault (unsigned integer, valid range: 0 <= value <= 1)
EditionFlagOrdered (unsigned integer, valid range: 0 <= value <= 1)
ChapterAtom (master)
ChapterAtom (master)
ChapterUID (unsigned integer, valid range: 1 <= value)
ChapterTimeStart (unsigned integer)
ChapterTimeEnd (unsigned integer)
ChapterFlagHidden (unsigned integer, valid range: 0 <= value <= 1)
ChapterFlagEnabled (unsigned integer, valid range: 0 <= value <= 1)
ChapterSegmentUID (binary, valid range: 1 <= length in bytes)
ChapterSegmentEditionUID (unsigned integer, valid range: 1 <= value)
ChapterPhysicalEquiv (unsigned integer)
ChapterTrack (master)
ChapterTrackNumber (unsigned integer, valid range: 1 <= value)
ChapterDisplay (master)
ChapterString (UTF-8 string)
ChapterLanguage (UTF-8 string)
ChapterCountry (UTF-8 string)
ChapterProcess (master)
ChapterProcessCodecID (unsigned integer)
ChapterProcessPrivate (binary)
ChapterProcessCommand (master)
ChapterProcessTime (unsigned integer)
ChapterProcessData (binary)
General notes
When splitting files mkvmerge(1) will correctly adjust the chapters as well. This means
that each file only includes the chapter entries that apply to it, and that the timestamps
will be offset to match the new timestamps of each output file.
mkvmerge(1) is able to copy chapters from Matroska source files unless this is explicitly
disabled with the --no-chapters option. The chapters from all sources (Matroska files, Ogg
files, MP4 files, chapter text files) are usually not merged but end up in separate
ChapterEditions. Only if chapters are read from several Matroska or XML files that share
the same edition UIDs will chapters be merged into a single ChapterEdition. If such a
merge is desired in other situations as well then the user has to extract the chapters
from all sources with mkvextract(1) first, merge the XML files manually and mux them
afterwards.
TAGS
Introduction
Matroska's tag system is similar to that of other containers: a set of KEY=VALUE pairs.
However, in Matroska these tags can also be nested, and both the KEY and the VALUE are
elements of their own. The example file example-tags-2.xml shows how to use this system.
Scope of the tags
Matroska tags do not automatically apply to the complete file. They can, but they also may
apply to different parts of the file: to one or more tracks, to one or more chapters, or
even to a combination of both. The Matroska specification[5] gives more details about this
fact.
One important fact is that tags are linked to tracks or chapters with the Targets Matroska
tag element, and that the UIDs used for this linking are not the track IDs mkvmerge(1)
uses everywhere. Instead the numbers used are the UIDs which mkvmerge(1) calculates
automatically (if the track is taken from a file format other than Matroska) or which are
copied from the source file if the track's source file is a Matroska file. Therefore it is
difficult to know which UIDs to use in the tag file before the file is handed over to
mkvmerge(1).
mkvmerge(1) knows two options with which you can add tags to Matroska files: The
--global-tags and the --tags options. The difference is that the former option,
--global-tags, will make the tags apply to the complete file by removing any of those
Targets elements mentioned above. The latter option, --tags, automatically inserts the UID
that mkvmerge(1) generates for the tag specified with the TID part of the --tags option.
Example
Let's say that you want to add tags to a video track read from an AVI. mkvmerge
--identify file.avi tells you that the video track's ID (do not mix this ID with the UID!)
is 0. So you create your tag file, leave out all Targets elements and call mkvmerge(1):
$ mkvmerge -o file.mkv --tags 0:tags.xml file.avi
Tag file format
mkvmerge(1) supports a XML based tag file format. The format is very closely modeled after
the Matroska specification[5]. Both the binary and the source distributions of MKVToolNix
come with a sample file called example-tags-2.xml which simply lists all known tags and
which can be used as a basis for real life tag files.
The basics are:
• The outermost element must be <Tags>.
• One logical tag is contained inside one pair of <Tag> XML tags.
• White spaces directly before and after tag contents are ignored.
Data types
The new Matroska tagging system only knows two data types, a UTF-8 string and a binary
type. The first is used for the tag's name and the <String> element while the binary type
is used for the <Binary> element.
As binary data itself would not fit into a XML file mkvmerge(1) supports two other methods
of storing binary data. If the contents of a XML tag starts with '@' then the following
text is treated as a file name. The corresponding file's content is copied into the
Matroska element.
Otherwise the data is expected to be Base64 encoded. This is an encoding that transforms
binary data into a limited set of ASCII characters and is used e.g. in email programs.
mkvextract(1) will output Base64 encoded data for binary elements.
The deprecated tagging system knows some more data types which can be found in the
official Matroska tag specs. As mkvmerge(1) does not support this system anymore these
types aren't described here.
Known tags for the XML file format
The following lists the supported XML tags, their data types and, where appropriate, the
valid range for their values:
Tags (master)
Tag (master)
Targets (master)
TargetTypeValue (unsigned integer)
TargetType (UTF-8 string)
TrackUID (unsigned integer)
EditionUID (unsigned integer)
ChapterUID (unsigned integer)
AttachmentUID (unsigned integer)
Simple (master)
Simple (master)
Name (UTF-8 string)
TagLanguage (UTF-8 string)
DefaultLanguage (unsigned integer)
String (UTF-8 string)
Binary (binary)
THE SEGMENT INFO XML FILES
With a segment info XML file it is possible to set certain values in the "segment
information" header field of a Matroska file. All of these values cannot be set via other
command line options.
Other "segment information" header fields can be set via command line options but not via
the XML file. This includes e.g. the --title and the --timestamp-scale options.
There are other elements that can be set neither via command line options nor via the XML
files. These include the following elements: DateUTC (also known as the "muxing date"),
MuxingApp, WritingApp and Duration. They're always set by mkvmerge(1) itself.
The following lists the supported XML tags, their data types and, where appropriate, the
valid range for their values:
Info (master)
SegmentUID (binary, valid range: length in bytes == 16)
SegmentFilename (UTF-8 string)
PreviousSegmentUID (binary, valid range: length in bytes == 16)
PreviousSegmentFilename (UTF-8 string)
NextSegmentUID (binary, valid range: length in bytes == 16)
NextSegmentFilename (UTF-8 string)
SegmentFamily (binary, valid range: length in bytes == 16)
ChapterTranslate (master)
ChapterTranslateEditionUID (unsigned integer)
ChapterTranslateCodec (unsigned integer)
ChapterTranslateID (binary)
MATROSKA FILE LAYOUT
The Matroska file layout is quite flexible. mkvmerge(1) will render a file in a
predefined way. The resulting file looks like this:
[EBML head] [segment {meta seek #1} [segment information] [track information]
{attachments} {chapters} [cluster 1] {cluster 2} ... {cluster n} {cues} {meta seek #2}
{tags}]
The elements in curly braces are optional and depend on the contents and options used. A
couple of notes:
• meta seek #1 includes only a small number of level 1 elements, and only if they
actually exist: attachments, chapters, cues, tags, meta seek #2. Older versions of
mkvmerge(1) used to put the clusters into this meta seek element as well. Therefore
some imprecise guessing was necessary to reserve enough space. It often failed. Now
only the clusters are stored in meta seek #2, and meta seek #1 refers to the meta seek
element #2.
• Attachment, chapter and tag elements are only present if they were added.
The shortest possible Matroska file would look like this:
[EBML head] [segment [segment information] [track information] [cluster 1]]
This might be the case for audio-only files.
EXTERNAL TIMESTAMP FILES
mkvmerge(1) allows the user to chose the timestamps for a specific track himself. This can
be used in order to create files with variable frame rate video or include gaps in audio.
A frame in this case is the unit that mkvmerge(1) creates separately per Matroska block.
For video this is exactly one frame, for audio this is one packet of the specific audio
type. E.g. for AC-3 this would be a packet containing 1536 samples.
Timestamp files that are used when tracks are appended to each other must only be
specified for the first part in a chain of tracks. For example if you append two files,
v1.avi and v2.avi, and want to use timestamps then your command line must look something
like this:
$ mkvmerge ... --timestamps 0:my_timestamps.txt v1.avi +v2.avi
There are four formats that are recognized by mkvmerge(1). The first line always contains
the version number. Empty lines, lines containing only whitespace and lines beginning with
'#' are ignored.
Timestamp file format v1
This format starts with the version line. The second line declares the default number of
frames per second. All following lines contain three numbers separated by commas: the
start frame (0 is the first frame), the end frame and the number of frames in this range.
The FPS is a floating point number with the dot '.' as the decimal point. The ranges can
contain gaps for which the default FPS is used. An example:
# timestamp format v1
assume 27.930
800,1000,25
1500,1700,30
Timestamp file format v2
In this format each line contains a timestamp for the corresponding frame. This timestamp
must be given in millisecond precision. It can be a floating point number, but it doesn't
have to be. You have to give at least as many timestamp lines as there are frames in the
track. The timestamps in this file must be sorted. Example for 25fps:
# timestamp format v2
0
40
80
Timestamp file format v3
In this format each line contains a duration in seconds followed by an optional number of
frames per second. Both can be floating point numbers. If the number of frames per second
is not present the default one is used. For audio you should let the codec calculate the
frame timestamps itself. For that you should be using 0.0 as the number of frames per
second. You can also create gaps in the stream by using the 'gap' keyword followed by the
duration of the gap. Example for an audio file:
# timestamp format v3
assume 0.0
25.325
7.530,38.236
gap, 10.050
2.000,38.236
Timestamp file format v4
This format is identical to the v2 format. The only difference is that the timestamps do
not have to be sorted. This format should almost never be used.
EXIT CODES
mkvmerge(1) exits with one of three exit codes:
• 0 -- This exit code means that muxing has completed successfully.
• 1 -- In this case mkvmerge(1) has output at least one warning, but muxing did
continue. A warning is prefixed with the text 'Warning:'. Depending on the issues
involved the resulting file might be ok or not. The user is urged to check both the
warning and the resulting file.
• 2 -- This exit code is used after an error occurred. mkvmerge(1) aborts right after
outputting the error message. Error messages range from wrong command line arguments
over read/write errors to broken files.
ENVIRONMENT VARIABLES
mkvmerge(1) uses the default variables that determine the system's locale (e.g. LANG and
the LC_* family). Additional variables:
MKVMERGE_DEBUG, MKVTOOLNIX_DEBUG and its short form MTX_DEBUG
The content is treated as if it had been passed via the --debug option.
MKVMERGE_ENGAGE, MKVTOOLNIX_ENGAGE and its short form MTX_ENGAGE
The content is treated as if it had been passed via the --engage option.
SEE ALSO
mkvinfo(1), mkvextract(1), mkvpropedit(1), mkvtoolnix-gui(1)
WWW
The latest version can always be found at the MKVToolNix homepage[6].
AUTHOR
Moritz Bunkus <moritz@bunkus.org>
Developer
NOTES
1. the Matroska website
http://www.matroska.org/
2. the IANA homepage
http://www.iana.org/assignments/media-types/
3. mkvmerge-identification-output-schema-v12.json
https://mkvtoolnix.download/doc/mkvmerge-identification-output-schema-v12.json
4. RFC 7159
https://tools.ietf.org/html/rfc7159
5. Matroska specification
http://matroska.org/technical/specs/index.html
6. the MKVToolNix homepage
https://mkvtoolnix.download/